This invention relates to an improved centralized monitor system for use in motor vehicles.
As is generally appreciated in the engineering field of motor vehicles e.g. automobiles, it is highly effective for securing safety in operation that the working condition or functioning of a number of essential parts incorporated therein be constantly monitored so that abnormal or prohibitive operating conditions, if any, occurring thereat will be promptly sensed. Such parts or objects to be monitored include, by way of example, functionings of various display lamps, capacities of batteries, quantities of stored fluid consumables e.g. engine oil, window-washer water, coolants and the like, or wear of brake linings, etc. For these monitoring purposes, there has been known a centralized monitor system for automobile use of the type by which a car driver, as seated, may check up instantly every item of the above described objects to be monitored. Such ordinary system generally includes a plurality of display means e.g. lamps for indication of respective trouble sources, a primary warning means e.g. a lamp for the first-warning purpose, and a corresponding plurality of sensors applied to respective parts or objects to be monitored, it being arranged that the display means are to be activated by the action of the respective sensors through associated switching circuits while the primary warning means is activated by the action of any one of the sensors through an associated common switching circuit. According to this arrangement, if an abnormality or failure of any one of parts or objects to be monitored is sensed by a respective sensor, a car driver will be given a first-warning by the primary lamp being lit up, locating then such part or object in question by the lighting of the corresponding display lamp. Usually, all of the display lamps and primary warning lamp are conveniently panelled on an overhead console in the automobile.
However, this conventional monitor system has had the problem that, in case of failures or malfunctions occurring in any one of the switching circuits for the display lamps due to possible damage of circuit elements or disconnections of circuit lines, etc., both the primary lamp and the respective display lamp are not energized even though the respective sensor has functioned satisfactorily to detect abnormalities, with the result that there is no indication of the abnormality at such corresponding part or object to be monitored.